Leaders of the two Koreas have agreed to end the Korean War, 65 years after hostilities ceased, in a wide-ranging joint announcement struck Friday, that includes working towards the complete denuclearization of the Korean Peninsula.

But the announcement, which largely steered clear of specifics regarding Pyongyang’s nuclear capabilities, faces major hurdles before any peace deal can be reached, which must also involve China and the US, both of whom were participants in the original conflict.

South Korean President Moon Jae-in and his North Korean counterpart, Kim Jong Un, signed the “Panmunjom Declaration for Peace, Prosperity and Unification on the Korean Peninsula,” at the demilitarized zone (DMZ), after an historic day of meetings, including a 30-minute private conversation the contents of which are unknown.

In separate speeches they promised a new era for the Korean Peninsula. Addressing the world’s media, Kim said the Koreas “will be reunited as one country.”

The Koreas went to war in 1950 when soldiers from the North Korean People’s Army invaded the South. Although the armed conflict ended three years later in 1953, with the signing of an armistice agreement, no formal peace treaty was ever signed, and technically, the Peninsula remains at war.

The landmark announcement followed a day heavy with symbolism and moments of what appeared to be genuine warmth between the two leaders, as the South Korean government put into action a program it had been preparing and rehearsing for weeks.

The stage is now set for Kim’s meeting with US President Donald Trump, due to take place later this year.

Trump and the rest of the US were asleep when today’s summit was taking place, but as the US East Coast woke up to the news that the Korean War could finally end, Trump tweeted all Americans “should be very proud of what is now taking place in Korea!”

“After a furious year of missile launches and nuclear testing, a historic meeting between North and South Korea,” he said. “Good things are happening, but only time will tell!”

Hoping for reunification

Following the signing ceremony Friday, Moon and Kim clasped hands and hugged in a symbolic act of togetherness. But while Friday was all smiles and handshakes, there are signs the declaration may contain potential pitfalls. Under the declaration, the two parties “confirmed the common goal of realizing, through complete denuclearization, a nuclear-free Korean Peninsula.”

What all sides mean by denuclearization has long been a sticking point, especially between North Korea and the US.

“Going into the US-North Korea summit, the key question remains whether North Korea would truly give up its nuclear weapons program,” Stratfor Asia Pacific analyst Evan Rees said in a statement.

“The phrasing of the Panmunjom Declaration refers to denuclearization of the peninsula, which could mean movement of US strategic assets, and a phased, rather than a rapid denuclearization — which goes against what the US has called for.”

Earlier in the day, Kim Jong Un said he hoped disagreements would not result in the non-implementation of the declaration, as they have done in the past, hinting he may be aware that the deal is not yet quite done.

Historic day

South Korea had scripted the meeting of the two leaders, down to the second, but it was Kim who delivered the most dramatic moment.

After he crossed the military demarcation line separating North and South Korea to shake hands with Moon, Kim invited him to step into the North.

The moment was greeted by gasps, cheers and applause from people watching it on a large screen in central Seoul, and at a conference center in nearby Ilsan, where the South Korean government had set up a sprawling media center for the thousands of journalists invited to watch history being made.

It was also perhaps the only spontaneous moment in what was a carefully choreographed affair, which those on the South Korean side had been practicing and rehearsing for weeks.

“President Moon briefly crossed over the MDL to the North,” the Blue House said in a statement, referring to the military demarcation line. “This was not a planned event.”

Kim Hyun, spokeswoman for Moon’s Democratic Party, told reporters the “whole nation and entire world passionately cheered” the meeting, adding that Kim’s crossing onto South Korean soil would be “remembered as a deeply moving moment.”

Writing in a visitor’s book upon entering the Peace House, where negotiations took place, Kim wrote “a new history begins now” and “an age of peace, at the starting point of history.”

Moon praised Kim’s “courageous and bold decision” to sit down for talks during their morning meeting. “Over the past seven decades we weren’t able to communicate, so I think we can talk the whole day today”, Moon said, drawing laughs from Kim.

Jean H Lee, a North Korea expert at the US based Wilson Center, said the images of Kim will have a great resonance in South Korea.

“For more than a decade, South Koreans have been cut off from North Korea due to tensions,” she said in a statement.

“Seeing Kim Jong Un live, chatting easily with their president, will no doubt have been jolt to South Koreans and remind them that the North Koreans are the same people in many ways, in language and shared history if not their political or economic structure.”

Sixty-five years of conflict

North of Seoul, along the Freedom Road, which stretches from the city to the Reunification Bridge leading into the demilitarized zone (DMZ), there was a sign of the changing mood: on one side of the highway, yellow and white balloons emblazoned with a blue map of Koreas; on the other, razor wire, guard towers and heavily armed soldiers patrolling the southern bank of the Han River which bisects the still-at-war Peninsula.

While fighting ended 65 years ago, the wounds of war are still very apparent. Families remain split by the conflict, unable to see their relatives on the other side, and some who lost relatives decades ago are still unaware of what fate befell them.

Near the DMZ Thursday, 51 people from the Korean War Veterans Revisit Korea Program had gathered to remember their relatives lost in that conflict and support peace and reunification.

“My father Karle Seydel was killed December 7, 1950 in the Chosun reservoir,” Ruth Hebert, who was from San Diego in California, told CNN. His body is believed to be still somewhere inside North Korea.

Hebert said she had spoken with South Koreans who had lost family members in the war and been separated from relatives by the partitioning of the Peninsula.

“We hope and pray that … this starts to really change,” she added. “There’s a hope with Japan, with Korea, with the Americans to recover remains. There may be a few (prisoners of war) alive but mostly now it’s down to remains.”

A formal end to the war will involve more than just the Koreas. Both China and the US, under the flag of the United Nations, were massively involved in the conflict, and would have to be signatories to an eventual peace treaty.